The present invention generally pertains to integrated circuit chips for electronic data processing systems and is particularly directed to preventing alteration of data that is stored within a secure area of an integrated circuit chip.
Integrated circuit chips that store secure data include a secure memory having a plurality of memory locations, with one or more predetermined locations being for the storage of unalterable secure data; and a memory control logic circuit coupled to the secure memory by an address bus for causing data to be stored in locations of the memory indicated by address signals provided on the address bus. The secure memory and the memory control logic circuit are contained within a secure area of the chip.
By delivering appropriate control signals to the memory control logic circuit, it may be possible to cause the memory control logic circuit to enable the secure data stored in the predetermined locations of the secure memory to be replaced by clandestine data that would enable the intended security of the chip to be compromised.